Proper syntax


 
Thread Tools Search this Thread
# 1  
Proper syntax

I'm new to Unix, and just had a quick question.

I'm writing a bash script, and I was wondering what proper programming etiquette was for piping. How many pipes is too many pipes?
Code:
OLDEST=$(find . -maxdepth 1 -type d -newermt 2012-07-01 ! -newermt
2012-07-30 | xargs ls -1td | tail -2)

echo "${OLDEST}\n"

My next step would be to tar those directories, then move them. I'm not asking if it's a matter of CAN I pipe it all, but SHOULD I pipe it all. As its proper to indent while in a loop, is there a unanimous rule for amount of pipes?

Thanks
# 2  
With a long series of pipes it can be hard to trap and respond correctly to an error.
More pipes makes that harder to. Learn about the PIPESTATUS array if you want to write solid bash and use lots of pipes.

Some operations require pipes to become more efficient, e.g., pipes "cost" less disk space. And leave behind no intermediate files.

The book 'Code Complete' recommends that a line of code be split with continuation "\" when it gets beyond the max line length on your screen: ~80 character positions, including leading tabs and spaces. You can also split on a pipe symbol. This is to provide readability for the next guy.
 

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

Test Your Knowledge in Computers #927
Difficulty: Medium
32-bit versions of the Unix time stamp will cease to work at 03:14:08 UTC on Tuesday, 19 January 2038.
True or False?

10 More Discussions You Might Find Interesting

1. Cybersecurity

Proper naming conventions

Hey guys, not sure should I post it here or in 'What is on Your Mind?' Iím discussing usage of DSL (domain specific language) in security tools with my colleagues. We haven't been able to reach an agreement over naming conventions. There are many tools using DSL: splunk, sumologic,... (2 Replies)
Discussion started by: Tobby P
2 Replies

2. What is on Your Mind?

Proper configuration management

Recently i started to work in new company. I will replace old admin who is going into retirement and he has been showing me his procedures for server, database and network administration. From first point of view: there is absolutely no configuration management involved how they deploy software... (0 Replies)
Discussion started by: solaris_user
0 Replies

3. Shell Programming and Scripting

Help with proper loop and variables

I have written a Bash Script that captures video via the Linux application DVgrab. When run my script prompts the terminal user to enter all the necessary information for the capture, save location, file name, file type capture duration etc... These are all in the form of #!/bin/bash echo... (5 Replies)
Discussion started by: Starcast
5 Replies

4. BSD

proper syntax of grep command

I'm learning UNIX on my mac (BSD), using a manual. I'm trying to figure out the grep command, and am getting something wrong. I've opened one of my files in NeoOffice and am looking for a string, the phrase 'I am writing.' I've been to some sites to get the proper syntax, and from what I can see... (5 Replies)
Discussion started by: Straitsfan
5 Replies

5. Shell Programming and Scripting

proper ordering of o/p values

Hi, Below is my script which creates a file: #!/bin/sh if then echo "Enter bill period " echo "Syntax: sh cpd.sh G08" exit fi sqlplus uname/pwd@dbname <<EOF set WRAP off set FEEDBACK off set PAGESIZE 0 set VERIFY off (14 Replies)
Discussion started by: ss_ss
14 Replies

6. Shell Programming and Scripting

getting proper o/p from a procedure in a script

foll. is my code snippet. #!/bin/ksh retVal=`sqlplus -s user/passwd@oracle_sid <<EOF SET SERVEROUTPUT ON SIZE 100000 DECLARE STATUS_VALUE CHAR; BEGIN SELECT temp1 INTO STATUS_VALUE FROM sai; DBMS_OUTPUT.PUT_LINE(STATUS_VALUE); END; / SET... (1 Reply)
Discussion started by: sainathdeg
1 Replies

7. UNIX for Dummies Questions & Answers

Proper use of prune...

My goal was to find any directories inside of any directory called "09_Client Original" not modified in the last 30 days. $ find /Volumes/Jobs_Volume/ -type d -name "09_Client Original" -exec find {} -mtime +30 -type d -maxdepth 1 \; The results of this find are passed along in a perl script... (1 Reply)
Discussion started by: guriboy
1 Replies

8. IP Networking

Proper routing

I have a series of new machines that are internet facing (have IP's that are accessible via the 'net) and it has internal facing interfaces. I need to be able to communicate back to the internal network to a specific server which processes monitoring and e-mail traffic. I've been told that I should... (3 Replies)
Discussion started by: BOFH
3 Replies

9. UNIX for Dummies Questions & Answers

Application servers, proper usage

Is it common in the Unix/Linux environment to install compute intensive applications on a Server system and have the client machines download the executables into memory at runtime to run locally? This model seems taxing to the network, and as I understand, has been largely abandoned in the... (1 Reply)
Discussion started by: jonwillog
1 Replies

10. Post Here to Contact Site Administrators and Moderators

Proper Forum Etiquette

I'm a frequent visitor to these forums. I generally enjoy topics that are posted as well as the responses. I really pickup a lot of new things to learn. However, there is one thing that does bother me here. (I dont mean to start a flame war, or any problems at all, just expressing some... (8 Replies)
Discussion started by: tarballed
8 Replies

Featured Tech Videos